1. Field of the Invention
The present invention generally relates to a frequency synthesizer. More particular, the present invention relates to a very precise frequency synthesizer featuring very accurate long-term phase and frequency.
2. Description of Related Arts
The conventional digital frequency synthesizer utilizes a delta-sigma fractional divider in PLL feedback loop and operates on N, N+1 basis, and usually PLL input is direct from crystal such as 14 MHz or 20 MHz. This results in jitter at much lower offset frequencies that requires larger area to suppress.